Here is a qwotation from the opening of the play, "The Phantom
of the Opera," that I just recieved in email. 

"The Opera ghost really existed.  He was not, as was long beleived,
 a creature of the imagination of the artists, the superstition of
 the managers, or a product of the absurd and impressionable brains
 of the young ladies of the ballet, the box-keepers, thier mothers,
 the cloak-room attendants or the concierge.  Yes, he existed in 
 flesh and blood, although he assumed the complete appearance of a 
 real phantom; that is to say, of a spectral shade."